1. Field of the Invention
The invention relates to a cover of a motor vehicle roof with a cover plate, a plastic frame which is foamed or injected and which runs around the edge of the cover plate, and an edge gap seal on the outside edge of the plastic frame. Furthermore, the subject matter of the invention is a process for producing one such cover.
2. Description of Related Art
A cover of the initially mentioned type for an openable vehicle roof is known for example from DE 197 07 145 C1. Here on the bottom of the cover plate there is a reinforcing frame which is securely joined to the cover plate by the plastic frame. The known cover has a peripheral edge gap seal which is inserted into the seal receiving groove of the plastic frame after producing the combination of the cover frame, reinforcing frame, and plastic frame by an injection or foaming process. This seal receiving groove is either milled or produced by a slide in a foaming tool, with which the plastic frame is foamed onto the cover plate and the reinforcing frame. This is a complex and expensive process which is moreover critical with respect to precision and process safety. In particular it must be stressed that the milling of the seal receiving groove requires that the corresponding equipment be made available. Aside from the fact that milling is an additional cycle, high wear of the cutting tool must be tolerated and a critical tolerance zone position must be considered. In addition, optical faults on the top of the plastic frame which typically consists of polyurethane cannot be avoided upon entry of the radius as a result of the milling equipment concept. Peripheral foaming by means of slides to form the seal receiving groove dictates a complex foaming tool, a relatively long cycle time by the slider function, a cleaning process and separation of the sliders, moreover deterioration of the foam flow as a result of the slider having to be expected. Finally, with respect to the separate edge gap seal, it must be stated that it is a relatively expensive individual part which requires tool costs, a high level of job planning and logistics as well as an additional installation process.
DE 196 24 715 C1 discloses another cover of the initially mentioned type of an openable vehicle roof which does not comprise a reinforcing frame. The plastic frame of this known cover has an initially free edge strip which extends to the outside and which can be bent with the formation of a hollow chamber and can be fixed with its outside edge near the peripheral edge of the cover plate adjacent to the plastic frame from underneath. To adapt to deviations in dimensions and unevenness in the edge gap between the roof recess and the cover, this hollow chamber is made adjustable. For this purpose, on the outside edge of the edge strip there is an inner surface section which after bending of the edge strip to form the hollow chamber on the opposite surface of the plastic frame can be adjustably fixed by means of a clamping profile strip. For this purpose, the clamping profile strip fits into a clamp groove of the frame body. The edge gap seal arrangement fixed by this hollow chamber as a result of its adjustment requirement is complex at least in installation. It is questionable whether the sealing function of this edge gap seal arrangement based on the hollow chamber which has been fixed in this way is ensured over the long term.
In view of this prior art, the object of this invention is to devise a cover of the originally mentioned type which can also be produced economically with respect to the edge gap seal and which ensures a permanently reliable sealing function. Furthermore, a process for producing one such cover will be made available.
Accordingly, the invention calls for integration of the edge gap seal into the outside edge of the plastic frame in the form of a lip which runs around the plastic outer frame and is fixed by a groove which has been formed in the outside edge of the plastic frame, a groove with a thin outside wall which forms this sealing lip. The cover is produced in the conventional manner by injecting or foaming of the plastic frame to the cover plate, however the groove which is open to the bottom and the lip which forms the edge gap seal being formed in doing so.
While basically the lip on the plastic frame inherently already makes available a sealing function relative to the pertinent contact surface of the vehicle roof, according to one especially advantageous development of the invention it is provided that in the groove there is a plastic insert of a material which is softer than the material of the plastic frame and thus always presses the lip against the pertinent contact surface of the vehicle roof. One additional advantage of the plastic insert is that other functions for the vehicle can be integrated into it, for example pinch protection, heating for the cover edge, an antenna, for example, a broadcast antenna or a GPS antenna, and the like.
The lip can be made with a raised outside contour to enhance the sealing function.
The base of the groove can pass into the lip via a weakening point which forms a hinge. In this way, during production the result is that a swivel point for forced mold removal in the formation of the groove by the foaming or injection process is made available. Upon later use in the vehicle roof the swivelling capacity of the lip is ensured by this weakening point also in the case in which the roof cutout which accommodates the cover is smaller than a stipulated nominal size.
The material for the plastic insert which is located in the groove can advantageously be foam, for example, a closed-pore foam such as microcellular rubber, for example.
To ensure the permanent seat of the plastic insert in the groove, the latter is advantageously adapted to the contour of the plastic insert. One especially advantageous embodiment calls for a groove which is roughly circular in cross section and a correspondingly shaped plastic insert. Here the outer lip is likewise convexly arched to the outside at least in one partial area.
The plastic insert can at least roughly completely fill the groove. But it can also have a cross section which only partially fills the cross section of the groove, can be made especially annular or inversely U-shaped in cross section and then can consist especially of an unfoamed plastic, for example rubber.
The cover can be made as a movable, especially raisable and/or slidable cover of an openable vehicle roof or as a roof element which is for example transparent or covered with solar cells and which is inserted immovably into the vehicle roof.
In the case of a movable cover, according to another advantageous development of the invention it is provided that the lip runs out to the bottom in a tapered drip end which can be easily made in the foaming or injection process. The cover plate of the movable cover can feasiblely be supported on a reinforcing frame. The latter can be cemented to the cover plate or also joined simply by the plastic frame surrounding the edge area of the reinforcing frame.
In the case of an immovably inserted cover it can be cemented or screwed to the vehicle roof, and in another embodiment of the invention the plastic frame can be made at the same time as a spacer which provides for a predetermined alignment of the top of the cover to the part of the vehicle roof which fits around the cover.
The plastic insert can be placed in the groove of the plastic frame in the course of injection or foaming of the plastic frame or in a subsequent step into the groove of the plastic frame.
According to one preferred approach, a prefabricated plastic insert can be fixed on a holding device in an injection or foaming tool which is used to form the plastic frame, then the plastic frame can be formed and when the injection or foaming tool for the plastic frame is opened the plastic insert can be released from the holding device.
In one modified process, after injecting or foaming the plastic frame to form the plastic insert a certain foam is placed in the groove of the plastic frame and foamed there.
These and further objects, features and advantages of the present invention will become apparent from the following description when taken in connection with the accompanying drawings which, for purposes of illustration only, show several embodiments in accordance with the present invention.